Pharyngeal arches

Embryology - 18 Apr 2024        Expand to Translate
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Introduction

Embryo Stage 14

The pharyngeal arches (branchial arch, Greek, branchial = gill) are a series of externally visible anterior tissue bands lying under the early brain that give rise to the structures of the head and neck. Each arch though initially formed from similar components will differentiate to form different head and neck structures. In humans, five arches form (1, 2, 3, 4 and 6) but only four are externally visible on the embryo.

Each arch has initially identical structures: an internal endodermal pouch, a mesenchymal (mesoderm and neural crest) core, a membrane (endoderm and ectoderm) and external cleft (ectoderm). Each arch mesenchymal core also contains similar components: blood vessel, nerve, muscular, cartilage.

The arch arteries undergo extensive remodelling during development of the vascular system, in general the inferior arteries have major contributions and superior arteries have minor contributions. The endothelium of arch arteries 1 and 2 has been shown to have different embryonic origin from 3-6 (second heart field).

Note is a draft page and this topic is currently covered in more detail on the head Development page.

Links: pharyngeal arch | head | neural crest | endocrine

Some Recent Findings

Branchial anomalies in children: A report of 105 surgical cases "Branchial anomalies (BAs) account for 20% of all congenital masses in children. We sought to review the incidence of involvement of individual anomalies, diagnostic methods, surgical treatment, and complications of BAs in children. ...A total of 33 (31.4%) cases presented with first BAs, 13 (12.4%) presented with second BAs, and 59 (56.2%) presented with third and fourth BAs, including 6 cases of congenital lower neck cutaneous fistula." Endothelium in the pharyngeal arches 3, 4 and 6 is derived from the second heart field "Oxygenated blood from the heart is directed into the systemic circulation through the aortic arch arteries (AAAs). The AAAs arise by remodeling of three symmetrical pairs of pharyngeal arch arteries (PAAs), which connect the heart with the paired dorsal aortae at mid-gestation. Aberrant PAA formation results in defects frequently observed in patients with lethal congenital heart disease. How the PAAs form in mammals is not understood. The work presented in this manuscript shows that the second heart field (SHF) is the major source of progenitors giving rise to the endothelium of the pharyngeal arches 3 - 6, while the endothelium in the pharyngeal arches 1 and 2 is derived from a different source. During the formation of the PAAs 3 - 6, endothelial progenitors in the SHF extend cellular processes toward the pharyngeal endoderm, migrate from the SHF and assemble into a uniform vascular plexus. This plexus then undergoes remodeling, whereby plexus endothelial cells coalesce into a large PAA in each pharyngeal arch." heart

More recent papers

This table allows an automated computer search of the external PubMed database using the listed "Search term" text link. This search now requires a manual link as the original PubMed extension has been disabled. The displayed list of references do not reflect any editorial selection of material based on content or relevance. References also appear on this list based upon the date of the actual page viewing. References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability. More? References | Discussion Page | Journal Searches | 2019 References | 2020 References Search term: Pharyngeal Arch <pubmed limit=5>Pharyngeal Arch</pubmed>

Pharyngeal Arch Development

• branchial arch (Gk. branchia= gill)
• arch consists of all 3 trilaminar embryo layers
• ectoderm- outside
• mesoderm- core of mesenchyme
• endoderm- inside

Pharyngeal Arch Tables

This table gives an overview of what each arch will contribute to the embryo.

Pharyngeal Arch	Nerve	Artery	Neural Crest (Skeletal Structures)	Muscles	Ligaments
1 (maxillary/mandibular)	trigeminal (CN V)	maxillary artery (terminal branches)	mandible, maxilla, malleus, incus	muscles of mastication, mylohyoid, tensor tympanic, ant. belly digastric	ant lig of malleus, sphenomandibular ligament
2 (hyoid)	facial (CN VII)	stapedial (embryonic) corticotympanic (adult)	stapes, styloid process, lesser cornu of hyoid, upper part of body of hyoid bone	muscles of facial expression, stapedius, stylohyoid, post. belly digastric	stylohyoid ligament
3	glossopharyngeal (CN IX)	common carotid, internal carotid arteries	greater cornu of hyoid, lower part of body of hyoid bone	stylopharyngeus
4	vagus (CN X) superior laryngeal branch	part of aortic arch (left), part right subclavian artery (right)	thyroid, cricoid, arytenoid, corniculate and cuneform cartilages	crycothyroid, soft palate levator veli palatini (not tensor veli palatini)
6	vagus (CN X) recurrent laryngeal branch	part of left pulmonary artery (left), part of right pulmonary artery (right)	thyroid, cricoid, arytenoid, corniculate and cuneform cartilages	larynx intrinsic muscles (not cricothyroid muscle)

Pharyngeal Arch Derivatives
Pharyngeal Arch	Nerve	Artery	Neural Crest (Skeletal Structures)	Muscles	Ligaments
1 (maxillary/mandibular)	trigeminal (V)	maxillary artery (terminal branches)	mandible, maxilla, malleus, incus	muscles of mastication, mylohyoid, tensor tympanic, ant. belly digastric	ant lig of malleus, sphenomandibular ligament
2 (hyoid)	facial (VII)	stapedial (embryonic) corticotympanic (adult)	stapes, styloid process, lesser cornu of hyoid, upper part of body of hyoid bone	muscles of facial expression, stapedius, stylohyoid, post. belly digastric	stylohyoid ligament
3	glossopharyngeal (IX)	common carotid, internal carotid arteries	greater cornu of hyoid, lower part of body of hyoid bone	stylopharyngeus
4	vagus (X) superior laryngeal branch	part of aortic arch (left), part right subclavian artery (right)	thyroid, cricoid, arytenoid, corniculate and cuneform cartilages	crycothyroid, soft palate levator veli palatini (not tensor veli palatini)
6	vagus (X) recurrent laryngeal branch	part of left pulmonary artery (left), part of right pulmonary artery (right)	thyroid, cricoid, arytenoid, corniculate and cuneform cartilages	larynx intrinsic muscles (not cricothyroid muscle)

Neural Crest

• Mesenchyme invaded by neural crest generating connective tissue components
• cartilage, bone, ligaments
• arises from midbrain and hindbrain region

Links: Neural Crest Development

Arch Features

Each arch contains: artery, cartilage, nerve, muscular component

Arches and Phanynx Form the face, tongue, lips, jaws, palate, pharynx and neck cranial nerves, sense organ components, glands

• Humans have 5 arches - 1, 2, 3, 4, 6 (Arch 5 does not form or regresses rapidly)
• from in rostro-caudal sequence, Arch 1 to 6 from week 4 onwards
• arch 1 and 2 appear at time of closure of cranial neuropore

• Face - mainly arch 1 and 2
• Neck components - arch 3 and 4 (arch 4 and 6 fuse)

Arch Features

• • arch
  • groove
    • externally separates each arch
      • also called a cleft
    • only first pair persist as external auditory meatus
  • pouch
    • internally separates each arch
    • pockets from the pharynx
  • membrane
    • ectoderm and endoderm contact regions
    • only first pair persist as tympanic membrane
• Pharyngeal Arch 1 (Mandibular Arch) has 2 prominances
  • smaller upper- maxillary forms maxilla, zygomatic bone and squamous part of temporal
  • larger lower- mandibular, forms mandible
• Pharyngeal Arch 2 (Hyoid Arch)
  • forms most of hyoid bone
• Arch 3 and 4
  • neck structures

Embryo Week: Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9

Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline

Pharyngeal Arch 3

Pouch 3

Pharyngeal pouch III is the embryonic origin of endodermal component of the thymus (that also has a neural crest contribution).

Additional Images

Historic Images

Historic Disclaimer - information about historic embryology pages

Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

Frazer JE. The second visceral arch and groove in the tubo-tympanic region. (1914) J Anat Physiol. 48(4): 391-408. PMID 17233005

• Second Pharyngeal Arch
• 

  12 mm embryo

• 

  16 mm embryo

• 

  27mm embryo

• 

  35mm embryo

Frazer JE. Development of the larynx. (1910) J Anat. 44: 156-191. PMID 17232839

• Embryonic Larynx Development
• 

  embryo 5 mm

• 

  embryo 6 mm

• 

  embryo 7.5 mm

• 

  embryo 8.5 mm

• 

  embryo 12 mm

• 

  embryo 6.6 mm

• 

  embryo 22 mm

• 

  embryo 35 mm

• 

  embryo 9.5 mm

Keibel F. and Mall FP. Manual of Human Embryology II. (1912) J. B. Lippincott Company, Philadelphia.

• Pharynx
• 

  Fig 314 Pharynx embryo Klb (Kromer-Pfannenstiel

• 

  Fig 315 Pharynx embryo Rob. Meyer No. 335

• 

  Fig 316 Pharynx embryo Hah

• 

  Fig 317 Pharynx embryo Rob. Meyer No. 300

• 

  Fig 318 model shown in Fig. 317

• 

  Fig 319 Pharyngeal pouches embryo Hah

• 

  Fig 320 Pharyngeal region embryo BR

• 

  Fig 321 Branchial derivatives embryo 11.7 mm

• 

  Fig 322 Pharynx embryo 21 mm

• 

  Fig 323 Pharynx embryo 24.4 mm

• 

  Fig 324 Branchiogenic derivatives in man

• 

  Fig 325 Section through embryo BR

• 

  Fig 326 Section through embryo BR

• 

  Fig 327 Section through embryo BR

• 

  Fig 328 Section through embryo BR

• 

  Fig 329 branchiogenic organs embryo 26 mm

• 

  Fig 330 Laryngeal region embryo Nat2

Terms

Head Terms (expand to view)

acephaly - term meaning absence of head, see skull and head abnormalities. branchial arch - see pharyngeal arch. brachycephaly - term meaning premature fusion of coronal suture, see skull and head abnormalities. clefting - the way in which the upper jaw forms from fusion of the smaller upper prominence of the first pharyngeal arch leads to a common congenital defect in this region called "clefting", which may involve either the upper lip, the palate or both structures, see palate and head abnormalities. coronal suture - skull term for the fibrous connective tissue joint that connects the frontal bone with the parietal bones. cranial fossae - skull term for the base bones of the cranial vault that form a container and support for the brain. cranial vault - skull term for the space formed by bones of the skull that enclose the brain. cysts - refers to a cervical sinus abnormality, remants of the cervical sinus remains as a fluid-filled cyst lined by an epithelium, see pharyngeal arch and head abnormalities. dolichocephaly - see scaphocephaly. exencephaly - term meaning brain outside skull, see skull and head abnormalities. fistula - refers to a pharyngeal membrane abnormality, a tract extends from pharynx (tonsillar fossa) beween the carotid arteries (internal and external) to open on side of neck, see pharyngeal arch and head abnormalities. lambdoid suture (lambdoidal suture) skull term for the fibrous connective tissue joint that connects the parietal bones with the occipital bone, and is continuous with the occipitomastoid suture. macrocephaly - term meaning large head, see hydrocephalus, skull and head abnormalities. Meckel's cartilage - (pharyngeal arch 1 cartilage) The mandible forms by intramembranous ossification beside this transient cartilage. The middle ear malleus and incus are thought to form from the ends of this cartilage. metopic suture - skull term for the fibrous connective tissue joint that connects the two fontal bones. In the adult skull this suture is not always present. micrencephaly - term meaning small brain, see neural, skull and head abnormalities. otocephaly - term meaning absence of lower jaw, see skull and head abnormalities. oxycephaly - (turricephaly) term meaning premature fusion of coronal suture + others, see skull and head abnormalities. pharyngeal arch - (branchial arch) a structure that forms in the cranial region of the embryo having contributions from all germ layers. In humans, the arches appear in week 4 (GA week 6) in a rostra-caudal sequence and are numbered (1, 2, 3, 4, and 6). Each arch contributes a different part of the head and neck and the associated components. pharyngeal cleft - (groove) surface ectoderm that externally separates each pharyngeal arch. In humans, only first pair persist as the outer ear external auditory meatus. pharyngeal groove - see pharyngeal cleft. pharyngeal membrane - surface ectoderm and pharynx endoderm contact region lying between each pharyngeal arch. In humans, only the first membrane pair persist as the tympanic membrane. pharyngeal pouch - pharynx endoderm internal out-pocketing that separates each pharyngeal arch. plagiocephaly - term meaning premature unilateral fusion of coronal or lambdoid sutures, see skull and head abnormalities. Reichardt's cartilage - (pharyngeal arch 2 cartilage) The superior portion of the hyoid forms the ventral portion of this cartilage and the middle ear stapes is thought to form from the ends of this cartilage. sagittal suture - skull term for the fibrous connective tissue joint that connects the two parietal bones in the midline. scaphocephaly - (dolichocephaly) term meaning premature fusion of sagittal suture, see skull and head abnormalities. sinuses - refers to a pharyngeal groove (cleft) abnormality, when a portion of the pharyngeal groove persists and opens to the skin surface, located laterally on the neck, see pharyngeal arch and head abnormalities. squamosal suture - skull term for the fibrous connective tissue joint that connects the squamous portion of the temporal bone with the parietal bones. suture - skull term for a fibrous connective tissue joint. In humans, the main sutures are coronal, sagittal, lambdoid and squamosal sutures, with the metopic suture (frontal suture) occurring as an anatomical variant in the adult skull. trigonocephaly - term meaning premature fusion of metopic suture, see skull and head abnormalities. turricephaly - see oxycephaly. vestiges - refers to a cartilaginous or bony developmental remnants that lie under the skin on side of neck, see pharyngeal arch and head abnormalities.

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Cite this page: Hill, M.A. (2024, April 18) Embryology Pharyngeal arches. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Pharyngeal_arches

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G